Wednesday, June 12, 2024

2024-06-19 / 10:00 ~ 11:00

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Pressure functions are key ideas in the thermodynamic formalism of dynamical systems. McMullen used the convexity of the pressure function to construct a metric, called a pressure metric, on the Teichmuller space and showed that it is a constant multiple of the Weil-Petersson metric. In the spirit of Sullivan's dictionary, McMullen applied the same idea to define a metric on the space of Blaschke products. In this talk, we will discuss Bridgeman-Taylor and McMullen's earlier works on the pressure metric, as well as recent developments in more generic settings. Then we will talk about pressure metrics on hyperbolic components in complex dynamics, as well as unsolved problems.

2024-06-18 / 10:00 ~ 11:00

학과 세미나/콜로퀴엄 - 위상수학 세미나:

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When does a topological branched self-covering of the sphere enjoy a holomorphic structure? William Thurston answered this question in the 1980s by using a holomorphic self-map of the Teichmuller space known as Thurston's pullback map. About 30 years later, Dylan Thurston took a different approach to the same question, reducing it to a one-dimensional dynamical problem. We will discuss both characterizations and their applications to various questions in complex dynamics.

2024-06-14 / 14:00 ~ 16:00

IBS-KAIST 세미나 - IBS-KAIST 세미나:

by 김현(IBS 의생명수학그룹)

In this talk, we discuss the paper, “Powerful and accurate detection of temporal gene expression patterns from multi-sample multi-stage single-cell transcriptomics data with TDEseq” by Y. Fan, L. Li and S. Sun, Genome Biology, 2024. Abstract We present a non-parametric statistical method called TDEseq that takes full advantage of smoothing splines basis functions to account for the dependence of multiple time points in scRNA-seq studies, and uses hierarchical structure linear additive mixed models to model the correlated cells within an individual. As a result, TDEseq demonstrates powerful performance in identifying four potential temporal expression patterns within a specific cell type. Extensive simulation studies and the analysis of four published scRNA-seq datasets show that TDEseq can produce well-calibrated p-values and up to 20% power gain over the existing methods for detecting temporal gene expression patterns. If you want to participate in the seminar, you need to enter IBS builiding (https://www.ibs.re.kr/bimag/visiting/). Please contact jaekkim@kaist.ac.kr if you first come IBS to get permission to enter IBS building.

2024-06-18 / 16:30 ~ 17:30

IBS-KAIST 세미나 - 이산수학: Paley-like quasi-random graphs arising from polynomials

by 유세민(IBS 이산수학그룹)

We provide new constructions of families of quasi-random graphs that behave like Paley graphs but are neither Cayley graphs nor Cayley sum graphs. These graphs give a unified perspective of studying various graphs defined by polynomials over finite fields, such as Paley graphs, Paley sum graphs, and graphs associated with Diophantine tuples and their generalizations from number theory. As an application, we provide new lower bounds on the clique number and independence number of general quasi-random graphs. In particular, we give a sufficient condition for the clique number of quasi-random graphs of order $n$ to be at least $(1-o(1))\log_{3.008}n$. Such a condition applies to many classical quasi-random graphs, including Paley graphs and Paley sum graphs, as well as some new Paley-like graphs we construct. If time permits, we also discuss some problems of diophantine tuples arising from number theory, which is our original motivation. This is joint work with Seoyoung Kim and Chi Hoi Yip.

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